There are at least two previous,investigations aimed at utilizing naturally occurring periodic phenomena in powder flow for the characterisation of particulate systems. Budny, Thomas J., Powder Technology, (Lausanne), 23, 197 (1979) used a Table Model Instron to measure the fluctuations in the shear force when a powder bed was sheared. Stick-slip amplitudes were related to the flow rate from a powder dispensing device, but not to general flow properties. Kaye, Brian H., Gratton-Lumatainen, Julie and Neil Faddis, Part. Part. Syst. Charact., (Weinheim), 12, 232 (1995) correlated the avalanching behaviour of a powder contained in a rotating drum with fines content.